Such ink supply apparatus for printing machines are already known in which each of the vibrating rollers is rotatably mounted on the movable end of a pivotal arm. By moving the pivotal arm as by an air cylinder, the vibrating roller is shiftable to a first position in which the roller is in contact with the ink fountain roller and away from the ink distributing roller, or alternatively to a second position in which the vibrating roller is in contact with the ink distributing roller and away from the ink fountain roller.
However, the conventional ink supply apparatus described requires groups of pivotal arms for changing over the position of the vibrating rollers and therefore has the problem of necessitating a large space for the installation of the arrangement.
An object of the present invention is to overcome the above problem and to provide an ink supply apparatus for printing machines which is reduced in the installation space for the vibrating rollers.